A man is sat at home watching T.V. when he hears a knock at the door. The man gets up and answers the door, to his astonishment there is a snail at the door.
The snail says “can I sell you some double glazing.” To which the man replies “no” and kicks him down the street.
Two weeks later there is another knock at the door. The man answers it and it is the snail again.
The snail then says “what did you do that for then.”